US3912558A - Method of MOS circuit fabrication - Google Patents

Method of MOS circuit fabrication Download PDF

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Publication number
US3912558A
US3912558A US466566A US46656674A US3912558A US 3912558 A US3912558 A US 3912558A US 466566 A US466566 A US 466566A US 46656674 A US46656674 A US 46656674A US 3912558 A US3912558 A US 3912558A
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US
United States
Prior art keywords
source
drain regions
layer
insulating material
oxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US466566A
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English (en)
Inventor
Robert L Luce
Joseph P Perry
James D Sansburry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fairchild Semiconductor Corp
Original Assignee
Fairchild Camera and Instrument Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fairchild Camera and Instrument Corp filed Critical Fairchild Camera and Instrument Corp
Priority to US466566A priority Critical patent/US3912558A/en
Priority to CA222,368A priority patent/CA1008973A/en
Priority to GB11462/75A priority patent/GB1494708A/en
Priority to JP3986875A priority patent/JPS5543631B2/ja
Priority to DE19752516393 priority patent/DE2516393A1/de
Priority to FR7513834A priority patent/FR2269792A1/fr
Application granted granted Critical
Publication of US3912558A publication Critical patent/US3912558A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
    • H01L23/482—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of lead-in layers inseparably applied to the semiconductor body
    • H01L23/485—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of lead-in layers inseparably applied to the semiconductor body consisting of layered constructions comprising conductive layers and insulating layers, e.g. planar contacts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
    • H01L23/291—Oxides or nitrides or carbides, e.g. ceramics, glass
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/13—Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304—Transistor
    • H01L2924/1306—Field-effect transistor [FET]
    • H01L2924/13091—Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S438/00—Semiconductor device manufacturing: process
    • Y10S438/914—Doping
    • Y10S438/919—Compensation doping

Definitions

  • An improved method of MOS circuit fabrication includes: formation of a region of first selected material on the surface of underlying material, removal of less than all of the first selected material from selected regions of the underlying material, formation of a layer 'of insulating material between the first selected material and the underlying material, conversion of the first selected material to a second selected material, and removal of the second'selected material to expose selected regions of the underlying material.
  • the first selected material is an oxide of boron
  • the second selected material is an oxide of phosphorous.
  • MOS circuits constructed in accordance with the prior art were susceptible to staining of the heavily doped source and drain region contact openings. Staining is a phenomenon well known in the art of semiconductor manufacture. The result of staining is to cause nonuniform, unpredictable penetration of the source or drain regions during formation of the metal connections with these regions.
  • the boron diffusion process and subsequent oxidations cause the creation of a thin layer of boron oxide on the p+ source or drain region surfaces beneath subsequently formed phosphorous oxide.
  • the phosphorous oxide etches very rapidily, the boron oxide etches very slowly. Consequently, extended etching times are necessary to completely remove the boron oxide, especially the last approximately 200 Angstroms.
  • the prolonged etch times necessary to remove the boron oxide cause excessive etching of other closely situated oxides and result in openings in the phosphorous oxide for electrical connections which are undesirably large, and which have excessively steep walls. These steep walls are prominent even though the oxide etches at a higher rate at the surface, than in the interior.
  • the p+ region silicon surface tends to remain hydrophilic, even though the oxide is removed.
  • Oxidized silicon is known to be hydrophilic, while silicon is hydrophobic. Because the transition from'hydrophilic to hydrophobic is often used as a test of the completeness of an etching process, it is difficult to discern when sufficient etching has occurred. Further, if the slow etching boron oxide region is not completely removed, it isdifficult to alloy metal electrical contact to the p-lsource or drain regions.
  • This invention provides a structure which does not depend upon creating a structure with a continuously decreasing etch rate for producing a continuously contoured oxide edge around an opening made for electrical contact.
  • the smoothly contoured oxide edges are obtained by thermal processing after providing openings to the source or drain region surfaces.
  • the contoured edges assist in assuring a reli' able metal to silicon electrical connection.
  • This invention also provides greater control over the size of an opening for an electrical connection to an underlying region and a more reliable etching process to expose these underlying regions. Additionally, the invention provides an indicator for completion of the etching process because the exposed silicon will be hydrophobic.
  • a first selected material if formed adjacent to and in contact with a surface of a semiconductor substrate. All, or substantially all, of the first selected material is removed from selected regions of the substrate surface. These selectedregions can be at locations where electrical contact to the source region, the drain region, or another region is desired.
  • a region of first insulating material is then formed on the previously underlying substrate. If any of the first selected material remains on the substrate, the first insulating material will separate the first selected material from the substrate.
  • a region of second insulating material is then formed on the surface of the wafer, and subjected to heat treatment. Openings for electrical connections are made, and a second heat treatment is performed. During this second heat treatment process step, insulating material formed on the exposed surfaces of the substrate is converted to a second selected material and removed. Electrical connections are then provided.
  • FIGS. la through 1d show the improved process for fabricating MOS circuits.
  • a layer of insulating material 11 (i.e. material 11a and 11b) is formed upon the surface of substrate of wafer 8.
  • substrate 10 is N conductivity type monocrystalline silicon, while insulating material 11 is silicon dioxide.
  • Insulating material 11 is removed from the surface of substrate 10 within a region 9. Typically, this is accomplished by an etching process; however, other processes may also be employed.
  • a region of insulating material 12 is then formed on substrate 10 throughout region 9, and may also be formed on insulating material 11.
  • This material typically will be silicon dioxide and will be thinner than insulating material 11; however, other non-electrically-conductive materials of appropriate thickness may also be employed.
  • a region of electrically conductive material 15 is formed on the surface of thin insulating material 12. To provide for electrical contact to other regions, a region of conductive material 15 may also be formed elsewhere on the surface of wafer 8, for example, on insulating material 11b, substrate 10, and region 18.
  • electrically conductive material 15a and 15b is formed by depositing a layer of material 15 across the surface of insulating materials 11 and 12, and then removing conductive material 15 from all portions of insulating materials 11 and 12, except at those selected regions where the material is desired, for example, as shown in FIG. 1a.
  • Conductive material 15 typically will be polycrystalline silicon, also known as polysilicon, although other electrical conductive materials may be also employed. Those regions of insulating material 12 not covered by patterned layer 15 are removed.
  • first selected material 14 is then formed across the surface of .wafer 8.
  • the first selected material is boron oxide. The boron from the oxide will diffuse into the surface of substrate 10 to form regions 17 and 18.
  • the first selected material may be any insulating material which contains dopant for the source and drain regions.
  • first selected material 14 are removed from substrate 10, for example at region 20. This removal will typically be accomplished by an etching process; however, other procedures may also be used. It should be noted that unlike the fabrication processes of the prior art, it is not necessary to remove all of the first selected material 14 from regions where electrical contact is desired. Any small amount remaining will be removed in a later step of the fabrication process. (FIG. lb shows a small amount remaining.)
  • a layer of first insulating material 19 is formed on the surface of the underlying material, for example, insulating material 11, regions 17 and 18, and conductive material 15.
  • First insulating material 19 typically will be silicon dioxide formed by an oxidation process, however, other materials may also be used. In carrying out this step, oxygen atoms easily pass through any remaining material 14 to combine with semiconductor material 10 and thus form an oxide.
  • a layer of second insulating material 22 is formed on the surface of the wafer 8.
  • the second insulating material 22 may be the same as the first insulating material 19; however, material 22 will have flow properties at elevated temperatures. Thus, elevated temperatures will soften the second insulating material 22 so that it will flow like viscous liquid.
  • the second insulating material 22 is subjected to elevated temperatures (a heat treatment) which causes smoothing of non-uniformities. Openings 24 for electrical connections to underlying material are then made, and the second insulating material 22 is again subjected to elevated temperatures.
  • This heat treatment causes smoothing of the edges 25 of the openings for electrical connections, which in prior art processes remain sharp.
  • region 20 (FIG. lb) and region 24 (FIG. 10) need not be the same size. For example, for purposes of alignment ease it may be convenient for region 24 to be disposed entirely within region 20.
  • Newly formed insulating material 21 is then converted to second selected material 21.
  • first selected material 14 is an oxide of boron
  • second selected material 21 is to be predominately an oxide of phosphorous
  • a POCl treatment well-known in semiconductor manufacture could be performed to convert the boron oxide to predominantely phosphorous oxide.
  • the surface of the source or drain regions 17 and 18 and the polycrystalline silicon gate are converted to lightly doped N- conductivity type material.
  • the relatively thin region of second selected material 21 is removed by any desired process, for example, an etch. Electrical connections 23 may then be formed for providing electrical signals to wafer 8.
  • Second selected material 21 must be a material whose chemical properties are sufficiently different relative to the initially formed insulating materials and other materials on the substrate that it can be selectively removed without significantly affecting surrounding materials.
  • second selected material may be fast etching compared to other materials in the structure.
  • the second selected material may contain dopant of opposite conductivity type to the first selected material.
  • the coversion of the first selected material in region 24 to second selected material may cause the source region and drain region to be doped N conductivity type to a very shallow depth. This causes the surface of the source region and drain region to become hydrophobic when clean, thereby furnishing visible indicator of when the etching process is complete.
  • the N type surface layer causes no adverse effects as it is sufficiently shallow to allow electrical contact to the p+ regions to be made by alloying through the surface layer.
  • edges 25 of the openings for electrical connections in region 24 will be smoothly contoured because of the heat treatment of insulating material 22. This eliminates the need for achieving the contour during an etching process as in the prior art. Further, the size of the openings for electrical contact are also controlled with more precision than in the prior art. This is accomplished by the conversion of first selected material to second selected material, For example, in one embodiment, any remaining portion of first selected material 14 (see FIG. 1b) plus additional insulating material which is formed beneath the first selected material is converted to a predominantly phosphorous oxide layer by means of a phosphorous diffusion, well-known in semiconductor manufacturing. This thin layer of predominantly phosphorous oxide may be then removed without additional masking step.
  • the method of claim 1 including between the steps of forming .a fourth layer of insulating material and forming openings for electrical connections, the step of heating said substrate and the attached materials to smooth out nonuniformities in selected ones of said attached materials.
  • boron is the P-type dopant used to give said source and drain regions a P- type conductivity and phosphorus is the N-type dopant used to convert the shallow surface layers of said source and drain regions to N-type conductivity.
  • said second selected material comprises an oxide of phosphorous.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Electrodes Of Semiconductors (AREA)
  • Weting (AREA)
  • Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
  • Insulated Gate Type Field-Effect Transistor (AREA)
US466566A 1974-05-03 1974-05-03 Method of MOS circuit fabrication Expired - Lifetime US3912558A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US466566A US3912558A (en) 1974-05-03 1974-05-03 Method of MOS circuit fabrication
CA222,368A CA1008973A (en) 1974-05-03 1975-03-18 Method of mos circuit fabrication
GB11462/75A GB1494708A (en) 1974-05-03 1975-03-19 Manufacture of semiconductor devices
JP3986875A JPS5543631B2 (fr) 1974-05-03 1975-04-03
DE19752516393 DE2516393A1 (de) 1974-05-03 1975-04-15 Verfahren zum herstellen von metall- oxyd-halbleiter-schaltungen
FR7513834A FR2269792A1 (fr) 1974-05-03 1975-05-02

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US466566A US3912558A (en) 1974-05-03 1974-05-03 Method of MOS circuit fabrication

Publications (1)

Publication Number Publication Date
US3912558A true US3912558A (en) 1975-10-14

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US466566A Expired - Lifetime US3912558A (en) 1974-05-03 1974-05-03 Method of MOS circuit fabrication

Country Status (6)

Country Link
US (1) US3912558A (fr)
JP (1) JPS5543631B2 (fr)
CA (1) CA1008973A (fr)
DE (1) DE2516393A1 (fr)
FR (1) FR2269792A1 (fr)
GB (1) GB1494708A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030952A (en) * 1974-04-18 1977-06-21 Fairchild Camera And Instrument Corporation Method of MOS circuit fabrication
US4097314A (en) * 1976-12-30 1978-06-27 Rca Corp. Method of making a sapphire gate transistor
US5409843A (en) * 1986-12-03 1995-04-25 Fujitsu, Ltd. Method of producing a semiconductor device by forming contacts after flowing a glass layer
GB2319890A (en) * 1996-11-26 1998-06-03 Nec Corp Field effect transistors

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53115173A (en) * 1977-03-18 1978-10-07 Hitachi Ltd Production of semiconductor device
JPS5492175A (en) * 1977-12-29 1979-07-21 Fujitsu Ltd Manufacture of semiconductor device
US4542037A (en) * 1980-04-28 1985-09-17 Fairchild Camera And Instrument Corporation Laser induced flow of glass bonded materials
CA1174285A (fr) * 1980-04-28 1984-09-11 Michelangelo Delfino Ecoulement de materiaux structurels de circuits integres obtenu au moyen d'un laser
EP1215205B1 (fr) 2000-12-08 2007-11-21 Sony Deutschland GmbH Linker molécules multifonctionnelles accordées pour le transport électronique de charge par les structures composites organique-inorganiques et l'utilisation de ces structures
US9701629B2 (en) 2000-12-08 2017-07-11 Sony Deutschland Gmbh Use of dithiocarbamate esters and bis-dithiocarbamate esters in the preparation of organic-inorganic nanocomposites

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3476619A (en) * 1966-09-13 1969-11-04 Motorola Inc Semiconductor device stabilization
US3756876A (en) * 1970-10-27 1973-09-04 Cogar Corp Fabrication process for field effect and bipolar transistor devices
US3825442A (en) * 1970-01-22 1974-07-23 Intel Corp Method of a semiconductor device wherein film cracking is prevented by formation of a glass layer
US3850708A (en) * 1970-10-30 1974-11-26 Hitachi Ltd Method of fabricating semiconductor device using at least two sorts of insulating films different from each other

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3476619A (en) * 1966-09-13 1969-11-04 Motorola Inc Semiconductor device stabilization
US3825442A (en) * 1970-01-22 1974-07-23 Intel Corp Method of a semiconductor device wherein film cracking is prevented by formation of a glass layer
US3756876A (en) * 1970-10-27 1973-09-04 Cogar Corp Fabrication process for field effect and bipolar transistor devices
US3850708A (en) * 1970-10-30 1974-11-26 Hitachi Ltd Method of fabricating semiconductor device using at least two sorts of insulating films different from each other

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030952A (en) * 1974-04-18 1977-06-21 Fairchild Camera And Instrument Corporation Method of MOS circuit fabrication
US4097314A (en) * 1976-12-30 1978-06-27 Rca Corp. Method of making a sapphire gate transistor
US5409843A (en) * 1986-12-03 1995-04-25 Fujitsu, Ltd. Method of producing a semiconductor device by forming contacts after flowing a glass layer
GB2319890A (en) * 1996-11-26 1998-06-03 Nec Corp Field effect transistors
GB2319890B (en) * 1996-11-26 1998-12-09 Nec Corp Semiconductor device having a reduced leakage current transistor and method of manufacturing the same

Also Published As

Publication number Publication date
JPS50142174A (fr) 1975-11-15
FR2269792A1 (fr) 1975-11-28
DE2516393A1 (de) 1975-11-13
GB1494708A (en) 1977-12-14
JPS5543631B2 (fr) 1980-11-07
CA1008973A (en) 1977-04-19

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